One vertex per element, one color per generator, with an edge from x to x·s.
(1,2)(3,8)(4,6)(5,7)(9,10)(11,14)(12,15)(13,16)(17,21)(18,22)(19,23)(20,24)(25,26)(27,37)(28,39)(29,34)(30,35)(31,40)(32,36)(33,38) involution — undirected(9,11)(10,14)(12,19)(13,18)(15,23)(16,22)(17,20)(21,24)(25,27,32,29)(26,33,36,39)(28,30,38,31)(34,40,37,35)(1,3,5,4)(2,6,7,8)(9,12,13,20)(10,15,16,24)(11,17,18,19)(14,21,22,23)(25,28,32,38)(26,33,36,39)(27,30,29,31)(34,35,37,40)(11,18)(14,22)(17,19)(21,23)(25,29,32,27)(26,34,36,37)(28,30,38,31)(33,40,39,35)(1,4,5,3)(2,6,7,8)(10,16)(14,22)(15,24)(21,23)(25,30,32,31)(26,35,36,40)(27,38,29,28)(33,34,39,37)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.